PRE-RELEASE
Solenoid valve, turbo bypass (605), E39
| Solenoid valve, turbo bypass (605), E39 |
| Location |
Solenoid valve, turbo bypass (605), E39
Located in engine bay, in middle of the intake manifold.
| Main task |
Check the function of the bypass valve.
| Type |
Pulse width modulated (PWM) solenoid valve where R is closed in unenergised state and C and W are always open and connected with each other. When the solenoid valve is unenergised, the bypass valve is connected to the control line after the throttle.
| Connection |
| 605 pin no. | Signal type | Description |
| 1 | Power supply, B+ | The solenoid valve is powered from fuse 7 in the petrol engine management system fuse box (727) via crimp connection J215. |
| 2 | Control | Solenoid valve control lead. The solenoid valve is grounded, pulse width modulated, from the ECM control module, E39 (590), pin 30(B). |
Diagram
| Function |
When the throttle closes an underpressure is quickly created in the intake manifold by means of combustion, while the overpressure before the throttle remains. In order to avoid pressure shocks in the intake manifold with subsequent jerking, when the throttle is re-opened the overpressure before the throttle must be released. The bypass valve signal line, which under normal driving is in connection with the outlet before the throttle, is then instead connected with the outlet after the throttle by means of a solenoid valve controlled by ECM, E39 (590).
By means of the underpressure in the intake manifold an underpressure is also obtained on the spring side in the bypass valve. The underpressure means that the valve opens and releases the overpressure from the compressor housing and the intake system in the intake hose. This connection remains active until the pressure before the throttle restabilises itself. After which the connection between the signal line and the outlet before the throttle is re-engaged.
